1. Field of the Invention
The present invention relates to a semiconductor device, and more particularly to a semiconductor device with an analog integrated circuit and a digital integrated circuit mounted thereon.
2. Description of the Related Art
The present invention also relates to a semiconductor module, and more particularly to a semiconductor module including a surface-mounted or built-in semiconductor device having an analog integrated circuit and a digital integrated circuit.
An example of this type of device is disclosed in Japanese Patent Laying-Open No. 2001-156209. According to this background art, a circuit element formation region is assigned to the central part of the upper surface of a silicon substrate, and outside of that region, a plurality of contact pads for signaling and a single contact pad for grounding are provided. A redistribution trace for signaling is provided to extend from the upper surface of the contact pad for signaling to the upper surface of an insulating film. A projection electrode is provided on the upper surface of a pad portion located at the leading end of the redistribution trace. A ground layer is provided on the upper surface of the insulating film on the circuit element formation region so as to avoid the redistribution trace for signaling and its neighboring area, and is connected to the contact pad for grounding via the redistribution trace for grounding. Another projection electrode is provided at a predetermined place on the upper surface of the ground layer.
However, when forming a plurality of integrated circuits, such as an analog integrated circuit and a digital integrated circuit, in a circuit element formation region, noise produced in a certain integrated circuit may affect another integrated circuit through a ground layer. Particularly, high frequency noise produced in the digital integrated circuit may destabilize the operation of the analog integrated circuit.